I have a container field that contains one link to an (externally stored) word doc or pdf per record. The container field is shown in a layout within a window from a different table (forgot the appropriate term sorry).

1. how do i open that doc/pdf from within the layout? (using menu options)

2. i want to make a button that triggers a script that should open the doc/pdf. but what command do i use to achieve it opening?

If you have interactive containers enabled, and you can't see the content on the layout, you may need to export it temporarily to open it up. Export field contents is the script step for that.

This also varies depending on how your file is hosted, how your containers are configured, and what client you are using to access the data (EG filemaker server 14, secure container storage, filemaker go client). You haven't specified anything about your setup.

Are you storing containers as a reference (link to file) instead of storing them internally in the database? If you store them internally it offers a lot more functionality than just storing a link to the document.